store_digest.cc
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1 /*
2  * Copyright (C) 1996-2022 The Squid Software Foundation and contributors
3  *
4  * Squid software is distributed under GPLv2+ license and includes
5  * contributions from numerous individuals and organizations.
6  * Please see the COPYING and CONTRIBUTORS files for details.
7  */
8 
9 /* DEBUG: section 71 Store Digest Manager */
10 
11 /*
12  * TODO: We probably do not track all the cases when
13  * storeDigestNoteStoreReady() must be called; this may prevent
14  * storeDigestRebuild/write schedule to be activated
15  */
16 
17 #include "squid.h"
18 #include "debug/Stream.h"
19 #include "event.h"
20 #include "globals.h"
21 #include "mgr/Registration.h"
22 #include "store_digest.h"
23 
24 #if USE_CACHE_DIGESTS
25 #include "CacheDigest.h"
26 #include "HttpReply.h"
27 #include "HttpRequest.h"
28 #include "internal.h"
29 #include "MemObject.h"
30 #include "PeerDigest.h"
31 #include "refresh.h"
32 #include "SquidConfig.h"
33 #include "Store.h"
34 #include "StoreSearch.h"
35 #include "util.h"
36 
37 #include <cmath>
38 
39 /*
40  * local types
41  */
42 
44 {
45 public:
47  int rebuild_lock = 0;
48  StoreEntry * rewrite_lock = nullptr;
49  StoreEntry * publicEntry = nullptr;
51  int rewrite_offset = 0;
52  int rebuild_count = 0;
53  int rewrite_count = 0;
54 };
55 
57 {
58 public:
59  int del_count = 0; /* #store entries deleted from store_digest */
60  int del_lost_count = 0; /* #store entries not found in store_digest on delete */
61  int add_count = 0; /* #store entries accepted to store_digest */
62  int add_coll_count = 0; /* #accepted entries that collided with existing ones */
63  int rej_count = 0; /* #store entries not accepted to store_digest */
64  int rej_coll_count = 0; /* #not accepted entries that collided with existing ones */
65 };
66 
67 /* local vars */
70 
71 /* local prototypes */
72 static void storeDigestRebuildStart(void *datanotused);
73 static void storeDigestRebuildResume(void);
74 static void storeDigestRebuildFinish(void);
75 static void storeDigestRebuildStep(void *datanotused);
76 static void storeDigestRewriteStart(void *);
77 static void storeDigestRewriteResume(void);
78 static void storeDigestRewriteFinish(StoreEntry * e);
80 static void storeDigestCBlockSwapOut(StoreEntry * e);
81 static void storeDigestAdd(const StoreEntry *);
82 
84 static uint64_t
86 {
87  /*
88  * To-Do: Bloom proved that the optimal filter utilization is 50% (half of
89  * the bits are off). However, we do not have a formula to calculate the
90  * number of _entries_ we want to pre-allocate for.
91  */
92  const uint64_t hi_cap = Store::Root().maxSize() / Config.Store.avgObjectSize;
93  const uint64_t lo_cap = 1 + Store::Root().currentSize() / Config.Store.avgObjectSize;
94  const uint64_t e_count = StoreEntry::inUseCount();
95  uint64_t cap = e_count ? e_count : hi_cap;
96  debugs(71, 2, "have: " << e_count << ", want " << cap <<
97  " entries; limits: [" << lo_cap << ", " << hi_cap << "]");
98 
99  if (cap < lo_cap)
100  cap = lo_cap;
101 
102  /* do not enforce hi_cap limit, average-based estimation may be wrong
103  *if (cap > hi_cap)
104  * cap = hi_cap;
105  */
106 
107  // Bug 4534: we still have to set an upper-limit at some reasonable value though.
108  // this matches cacheDigestCalcMaskSize doing (cap*bpe)+7 < INT_MAX
109  const uint64_t absolute_max = (INT_MAX -8) / Config.digest.bits_per_entry;
110  if (cap > absolute_max) {
111  static time_t last_loud = 0;
112  if (last_loud < squid_curtime - 86400) {
113  debugs(71, DBG_IMPORTANT, "WARNING: Cache Digest cannot store " << cap << " entries. Limiting to " << absolute_max);
114  last_loud = squid_curtime;
115  } else {
116  debugs(71, 3, "WARNING: Cache Digest cannot store " << cap << " entries. Limiting to " << absolute_max);
117  }
118  cap = absolute_max;
119  }
120 
121  return cap;
122 }
123 #endif /* USE_CACHE_DIGESTS */
124 
125 void
127 {
128  Mgr::RegisterAction("store_digest", "Store Digest", storeDigestReport, 0, 1);
129 
130 #if USE_CACHE_DIGESTS
132  store_digest = NULL;
133  debugs(71, 3, "Local cache digest generation disabled");
134  return;
135  }
136 
137  const uint64_t cap = storeDigestCalcCap();
139  debugs(71, DBG_IMPORTANT, "Local cache digest enabled; rebuild/rewrite every " <<
140  (int) Config.digest.rebuild_period << "/" <<
141  (int) Config.digest.rewrite_period << " sec");
142 
144 #else
145  store_digest = NULL;
146  debugs(71, 3, "Local cache digest is 'off'");
147 #endif
148 }
149 
150 /* called when store_rebuild completes */
151 void
153 {
154 #if USE_CACHE_DIGESTS
155 
159  }
160 
161 #endif
162 }
163 
164 //TODO: this seems to be dead code. Is it needed?
165 void
167 {
168 #if USE_CACHE_DIGESTS
169 
171  return;
172  }
173 
174  assert(entry && store_digest);
175  debugs(71, 6, "storeDigestDel: checking entry, key: " << entry->getMD5Text());
176 
177  if (!EBIT_TEST(entry->flags, KEY_PRIVATE)) {
178  if (!store_digest->contains(static_cast<const cache_key *>(entry->key))) {
180  debugs(71, 6, "storeDigestDel: lost entry, key: " << entry->getMD5Text() << " url: " << entry->url() );
181  } else {
183  store_digest->remove(static_cast<const cache_key *>(entry->key));
184  debugs(71, 6, "storeDigestDel: deled entry, key: " << entry->getMD5Text());
185  }
186  }
187 #else
188  (void)entry;
189 #endif //USE_CACHE_DIGESTS
190 }
191 
192 void
194 {
195 #if USE_CACHE_DIGESTS
196 
198  return;
199  }
200 
201  if (store_digest) {
202  static const SBuf label("store");
203  cacheDigestReport(store_digest, label, e);
204  storeAppendPrintf(e, "\t added: %d rejected: %d ( %.2f %%) del-ed: %d\n",
209  storeAppendPrintf(e, "\t collisions: on add: %.2f %% on rej: %.2f %%\n",
212  } else {
213  storeAppendPrintf(e, "store digest: disabled.\n");
214  }
215 #else
216  (void)e;
217 #endif //USE_CACHE_DIGESTS
218 }
219 
220 /*
221  * LOCAL FUNCTIONS
222  */
223 
224 #if USE_CACHE_DIGESTS
225 
226 /* should we digest this entry? used by storeDigestAdd() */
227 static int
229 {
230  /* add some stats! XXX */
231 
232  debugs(71, 6, "storeDigestAddable: checking entry, key: " << e->getMD5Text());
233 
234  /* check various entry flags (mimics StoreEntry::checkCachable XXX) */
235 
236  if (EBIT_TEST(e->flags, KEY_PRIVATE)) {
237  debugs(71, 6, "storeDigestAddable: NO: private key");
238  return 0;
239  }
240 
241  if (EBIT_TEST(e->flags, ENTRY_NEGCACHED)) {
242  debugs(71, 6, "storeDigestAddable: NO: negative cached");
243  return 0;
244  }
245 
246  if (EBIT_TEST(e->flags, RELEASE_REQUEST)) {
247  debugs(71, 6, "storeDigestAddable: NO: release requested");
248  return 0;
249  }
250 
252  debugs(71, 6, "storeDigestAddable: NO: wrong content-length");
253  return 0;
254  }
255 
256  /* do not digest huge objects */
257  if (e->swap_file_sz > (uint64_t )Config.Store.maxObjectSize) {
258  debugs(71, 6, "storeDigestAddable: NO: too big");
259  return 0;
260  }
261 
262  /* still here? check staleness */
263  /* Note: We should use the time of the next rebuild, not (cur_time+period) */
265  debugs(71, 6, "storeDigestAdd: entry expires within " << Config.digest.rebuild_period << " secs, ignoring");
266  return 0;
267  }
268 
269  /*
270  * idea: how about also skipping very fresh (thus, potentially
271  * unstable) entries? Should be configurable through
272  * cd_refresh_pattern, of course.
273  */
274  /*
275  * idea: skip objects that are going to be purged before the next
276  * update.
277  */
278  return 1;
279 }
280 
281 static void
283 {
284  assert(entry && store_digest);
285 
286  if (storeDigestAddable(entry)) {
288 
289  if (store_digest->contains(static_cast<const cache_key *>(entry->key)))
291 
292  store_digest->add(static_cast<const cache_key *>(entry->key));
293 
294  debugs(71, 6, "storeDigestAdd: added entry, key: " << entry->getMD5Text());
295  } else {
297 
298  if (store_digest->contains(static_cast<const cache_key *>(entry->key)))
300  }
301 }
302 
303 /* rebuilds digest from scratch */
304 static void
306 {
308  /* prevent overlapping if rebuild schedule is too tight */
309 
310  if (sd_state.rebuild_lock) {
311  debugs(71, DBG_IMPORTANT, "storeDigestRebuildStart: overlap detected, consider increasing rebuild period");
312  return;
313  }
314 
316  debugs(71, 2, "storeDigestRebuildStart: rebuild #" << sd_state.rebuild_count + 1);
317 
318  if (sd_state.rewrite_lock) {
319  debugs(71, 2, "storeDigestRebuildStart: waiting for Rewrite to finish.");
320  return;
321  }
322 
324 }
325 
327 static bool
329 {
330  const uint64_t cap = storeDigestCalcCap();
332  uint64_t diff;
333  if (cap > store_digest->capacity)
334  diff = cap - store_digest->capacity;
335  else
336  diff = store_digest->capacity - cap;
337  debugs(71, 2, store_digest->capacity << " -> " << cap << "; change: " <<
338  diff << " (" << xpercentInt(diff, store_digest->capacity) << "%)" );
339  /* avoid minor adjustments */
340 
341  if (diff <= store_digest->capacity / 10) {
342  debugs(71, 2, "small change, will not resize.");
343  return false;
344  } else {
345  debugs(71, 2, "big change, resizing.");
347  }
348  return true;
349 }
350 
351 /* called be Rewrite to push Rebuild forward */
352 static void
354 {
358  /* resize or clear */
359 
360  if (!storeDigestResize())
361  store_digest->clear(); /* not clean()! */
362 
364 
365  eventAdd("storeDigestRebuildStep", storeDigestRebuildStep, NULL, 0.0, 1);
366 }
367 
368 /* finishes swap out sequence for the digest; schedules next rebuild */
369 static void
371 {
375  debugs(71, 2, "storeDigestRebuildFinish: done.");
376  eventAdd("storeDigestRebuildStart", storeDigestRebuildStart, NULL, (double)
378  /* resume pending Rewrite if any */
379 
382 }
383 
384 /* recalculate a few hash buckets per invocation; schedules next step */
385 static void
387 {
388  /* TODO: call Store::Root().size() to determine this.. */
389  int count = Config.Store.objectsPerBucket * (int) ceil((double) store_hash_buckets *
392 
393  debugs(71, 3, "storeDigestRebuildStep: buckets: " << store_hash_buckets << " entries to check: " << count);
394 
395  while (count-- && !sd_state.theSearch->isDone() && sd_state.theSearch->next())
397 
398  /* are we done ? */
399  if (sd_state.theSearch->isDone())
401  else
402  eventAdd("storeDigestRebuildStep", storeDigestRebuildStep, NULL, 0.0, 1);
403 }
404 
405 /* starts swap out sequence for the digest */
406 static void
408 {
410  /* prevent overlapping if rewrite schedule is too tight */
411 
412  if (sd_state.rewrite_lock) {
413  debugs(71, DBG_IMPORTANT, "storeDigestRewrite: overlap detected, consider increasing rewrite period");
414  return;
415  }
416 
417  debugs(71, 2, "storeDigestRewrite: start rewrite #" << sd_state.rewrite_count + 1);
418 
419  const char *url = internalLocalUri("/squid-internal-periodic/", SBuf(StoreDigestFileName));
420  const auto mx = MasterXaction::MakePortless<XactionInitiator::initCacheDigest>();
421  auto req = HttpRequest::FromUrlXXX(url, mx);
422 
423  RequestFlags flags;
424  flags.cachable = true;
425 
426  StoreEntry *e = storeCreateEntry(url, url, flags, Http::METHOD_GET);
427  assert(e);
429  debugs(71, 3, "storeDigestRewrite: url: " << url << " key: " << e->getMD5Text());
430  e->mem_obj->request = req;
431 
432  /* wait for rebuild (if any) to finish */
433  if (sd_state.rebuild_lock) {
434  debugs(71, 2, "storeDigestRewriteStart: waiting for rebuild to finish.");
435  return;
436  }
437 
439 }
440 
441 static void
443 {
444  StoreEntry *e;
445 
451  /* setting public key will mark the old digest entry for removal once unlocked */
452  e->setPublicKey();
453  if (const auto oldEntry = sd_state.publicEntry) {
454  oldEntry->release(true);
455  sd_state.publicEntry = nullptr;
456  oldEntry->unlock("storeDigestRewriteResume");
457  }
458  assert(e->locked());
459  sd_state.publicEntry = e;
460  /* fake reply */
461  HttpReply *rep = new HttpReply;
462  rep->setHeaders(Http::scOkay, "Cache Digest OK",
463  "application/cache-digest", (store_digest->mask_size + sizeof(sd_state.cblock)),
465  debugs(71, 3, "storeDigestRewrite: entry expires on " << rep->expires <<
466  " (" << std::showpos << (int) (rep->expires - squid_curtime) << ")");
467  e->buffer();
468  e->replaceHttpReply(rep);
470  e->flush();
471  eventAdd("storeDigestSwapOutStep", storeDigestSwapOutStep, sd_state.rewrite_lock, 0.0, 1, false);
472 }
473 
474 /* finishes swap out sequence for the digest; schedules next rewrite */
475 static void
477 {
479  e->complete();
480  e->timestampsSet();
481  debugs(71, 2, "storeDigestRewriteFinish: digest expires at " << e->expires <<
482  " (" << std::showpos << (int) (e->expires - squid_curtime) << ")");
483  /* is this the write order? @?@ */
484  e->mem_obj->unlinkRequest();
487  eventAdd("storeDigestRewriteStart", storeDigestRewriteStart, NULL, (double)
489  /* resume pending Rebuild if any */
490 
493 }
494 
495 /* swaps out one digest "chunk" per invocation; schedules next swap out */
496 static void
498 {
499  StoreEntry *e = static_cast<StoreEntry *>(data);
500  int chunk_size = Config.digest.swapout_chunk_size;
502  assert(e);
503  /* _add_ check that nothing bad happened while we were waiting @?@ @?@ */
504 
505  if (static_cast<uint32_t>(sd_state.rewrite_offset + chunk_size) > store_digest->mask_size)
507 
508  e->append(store_digest->mask + sd_state.rewrite_offset, chunk_size);
509 
510  debugs(71, 3, "storeDigestSwapOutStep: size: " << store_digest->mask_size <<
511  " offset: " << sd_state.rewrite_offset << " chunk: " <<
512  chunk_size << " bytes");
513 
514  sd_state.rewrite_offset += chunk_size;
515 
516  /* are we done ? */
517  if (static_cast<uint32_t>(sd_state.rewrite_offset) >= store_digest->mask_size)
519  else
520  eventAdd("storeDigestSwapOutStep", storeDigestSwapOutStep, data, 0.0, 1, false);
521 }
522 
523 static void
525 {
526  memset(&sd_state.cblock, 0, sizeof(sd_state.cblock));
535  e->append((char *) &sd_state.cblock, sizeof(sd_state.cblock));
536 }
537 
538 #endif /* USE_CACHE_DIGESTS */
539 
unsigned char bits_per_entry
Definition: PeerDigest.h:34
SQUIDCEXTERN double xpercent(double part, double whole)
Definition: util.c:40
virtual void buffer()
Definition: store.cc:1579
static void storeDigestRebuildStep(void *datanotused)
unsigned char cache_key
Store key.
Definition: forward.h:29
#define EBIT_SET(flag, bit)
Definition: defines.h:67
uint64_t capacity
Definition: CacheDigest.h:57
virtual void flush()
Definition: store.cc:1590
MemObject * mem_obj
Definition: Store.h:219
time_t rewrite_period
Definition: SquidConfig.h:495
static int storeDigestAddable(const StoreEntry *e)
void clear()
reset the digest mask and counters
Definition: CacheDigest.cc:79
const char * url() const
Definition: store.cc:1544
@ KEY_PRIVATE
Definition: enums.h:102
time_t rebuild_period
Definition: SquidConfig.h:494
StoreDigestCBlock cblock
Definition: store_digest.cc:46
void storeAppendPrintf(StoreEntry *e, const char *fmt,...)
Definition: store.cc:830
StoreSearchPointer theSearch
Definition: store_digest.cc:50
Definition: SBuf.h:87
StoreEntry * publicEntry
points to the previous store entry with the digest
Definition: store_digest.cc:49
int objectsPerBucket
Definition: SquidConfig.h:269
bool setPublicKey(const KeyScope keyScope=ksDefault)
Definition: store.cc:550
void updateCapacity(uint64_t newCapacity)
changes mask size to fit newCapacity, resets bits to 0
Definition: CacheDigest.cc:86
uint16_t flags
Definition: Store.h:230
static StoreDigestState sd_state
Definition: store_digest.cc:68
time_t expires
Definition: Store.h:224
void replaceHttpReply(const HttpReplyPointer &, const bool andStartWriting=true)
Definition: store.cc:1683
void remove(const cache_key *key)
Definition: CacheDigest.cc:140
@ ENTRY_BAD_LENGTH
Definition: enums.h:114
const char * StoreDigestFileName
time_t expires
Definition: HttpReply.h:44
#define NULL
Definition: types.h:166
void cacheDigestReport(CacheDigest *cd, const SBuf &label, StoreEntry *e)
Definition: CacheDigest.cc:245
static void storeDigestRewriteFinish(StoreEntry *e)
short int required
Definition: PeerDigest.h:21
int bits_per_entry
Definition: SquidConfig.h:493
void storeDigestDel(const StoreEntry *entry)
#define INT_MAX
Definition: types.h:76
#define EBIT_TEST(flag, bit)
Definition: defines.h:69
@ RELEASE_REQUEST
prohibits making the key public
Definition: enums.h:98
int unlock(const char *context)
Definition: store.cc:444
static void storeDigestRewriteResume(void)
static size_t inUseCount()
Definition: store.cc:196
store_status_t store_status
Definition: Store.h:242
#define assert(EX)
Definition: assert.h:19
void storeDigestNoteStoreReady(void)
virtual void next(void(callback)(void *cbdata), void *cbdata)=0
Version const CacheDigestVer
Definition: peer_digest.cc:55
void EVH void double
Definition: stub_event.cc:16
char * mask
Definition: CacheDigest.h:58
virtual bool isDone() const =0
virtual StoreEntry * currentItem()=0
uint64_t del_count
Definition: CacheDigest.h:56
@ ENTRY_SPECIAL
Definition: enums.h:84
StoreSearch * search()
Definition: Controller.cc:211
static EVH storeDigestSwapOutStep
Definition: store_digest.cc:79
@ STORE_OK
Definition: enums.h:50
time_t squid_curtime
Definition: stub_libtime.cc:20
StoreEntry * storeCreateEntry(const char *url, const char *logUrl, const RequestFlags &flags, const HttpRequestMethod &method)
Definition: store.cc:734
static bool storeDigestResize()
void storeDigestReport(StoreEntry *e)
void EVH(void *)
Definition: event.h:18
static void storeDigestRebuildResume(void)
virtual uint64_t currentSize() const override
current size
Definition: Controller.cc:173
int rebuild_lock
bucket number
Definition: store_digest.cc:47
virtual uint64_t maxSize() const override
Definition: Controller.cc:159
void complete()
Definition: store.cc:1006
void add(const cache_key *key)
Definition: CacheDigest.cc:107
short int current
Definition: PeerDigest.h:20
struct SquidConfig::@110 onoff
bool timestampsSet()
Definition: store.cc:1371
static uint64_t storeDigestCalcCap()
calculates digest capacity
Definition: store_digest.cc:85
void unlinkRequest()
Definition: MemObject.h:55
static HttpRequest * FromUrlXXX(const char *url, const MasterXaction::Pointer &, const HttpRequestMethod &method=Http::METHOD_GET)
Definition: HttpRequest.cc:529
uint64_t swap_file_sz
Definition: Store.h:228
bool contains(const cache_key *key) const
Definition: CacheDigest.cc:93
int refreshCheckDigest(const StoreEntry *entry, time_t delta)
Definition: refresh.cc:611
#define DBG_IMPORTANT
Definition: Stream.h:41
CacheDigest * store_digest
struct SquidConfig::@118 digest
int digest_generation
Definition: SquidConfig.h:315
int64_t maxObjectSize
Definition: SquidConfig.h:271
int64_t avgObjectSize
Definition: SquidConfig.h:270
unsigned char hash_func_count
Definition: PeerDigest.h:35
int rebuild_chunk_percentage
Definition: SquidConfig.h:497
int store_hash_buckets
virtual void append(char const *, int)
Appends a c-string to existing packed data.
Definition: store.cc:778
void setHeaders(Http::StatusCode status, const char *reason, const char *ctype, int64_t clen, time_t lmt, time_t expires)
Definition: HttpReply.cc:167
@ ENTRY_NEGCACHED
Definition: enums.h:112
static void storeDigestRebuildFinish(void)
int locked() const
Definition: Store.h:144
uint32_t mask_size
Definition: CacheDigest.h:59
@ scOkay
Definition: StatusCode.h:26
void RegisterAction(char const *action, char const *desc, OBJH *handler, int pw_req_flag, int atomic)
Definition: Registration.cc:16
@ METHOD_GET
Definition: MethodType.h:25
static void storeDigestCBlockSwapOut(StoreEntry *e)
uint64_t count
Definition: CacheDigest.h:55
char * internalLocalUri(const char *dir, const SBuf &name)
Definition: internal.cc:130
size_t swapout_chunk_size
Definition: SquidConfig.h:496
static StoreDigestStats sd_stats
Definition: store_digest.cc:69
SQUIDCEXTERN int xpercentInt(double part, double whole)
Definition: util.c:46
#define debugs(SECTION, LEVEL, CONTENT)
Definition: Stream.h:196
HttpRequestPointer request
Definition: MemObject.h:188
int CacheDigestHashFuncCount
const char * getMD5Text() const
Definition: store.cc:204
static void storeDigestRewriteStart(void *)
void eventAdd(const char *name, EVH *func, void *arg, double when, int weight, bool cbdata)
Definition: event.cc:107
void storeDigestInit(void)
class SquidConfig Config
Definition: SquidConfig.cc:12
int unsigned int
Definition: stub_fd.cc:19
struct SquidConfig::@108 Store
static void storeDigestRebuildStart(void *datanotused)
static void storeDigestAdd(const StoreEntry *)
StoreEntry * rewrite_lock
points to store entry with the digest
Definition: store_digest.cc:48
Controller & Root()
safely access controller singleton
Definition: Controller.cc:934

 

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